Combination safety socket and fuse box



Dec, 29, 1964 H. F. MARTIN COMBINATION SAFETY SOCKET AND FUSE BOX Filed March 28, 1962 INVENTOR. HOWARDF. MARTIN ATTORNEYS United States Patent This invention relates to electrical devices and is particularly concerned with a novel sort of extension having fuses at the outlet end thereof.

In many instances it is desired to operate a plurality of appliances or tools from a single or double outlet and this involves considerable inconvenience in changing the connections to the appliances or the tools and also prevents the operation of more than one or two of the appliances or tools at one time. t

The present invention proposes the provision of an extension means adapted for plugging into a receptacle at one end and having multiple outlets at the other end for receiving the plugs for a plurality of tools or appliances.

Still further, the present invention is concerned with an arrangement for individually fusing the plurality of outlets at the one end of the extension and incorporating therein a shut off switch or an automatic switch so that the said individual fuses can be changed without danger of disconnecting the entire outlet end of the extension when the fuses are to be changed.

The primary objective of the present invention, there fore, is the provision of an extension arrangement having individually fused outlet circuits.

Another object of this invention is the provision of an extension having fused outlet circuits with means for automatically disconnecting the source of electrical energy from the outlet end of the extension when the fuses are to be changed,

A still further object of this invention is the provision of an extension having a multiple outlet arrangement at one end so constructed that the multiple outlet end is energized only when it is resting in a predetermined position.

Still further, an object of this invention is the provision of a relatively inexpensive multiple outlet individually fused outlet extension arrangement as described above.

These and other objects and advantages of this invention will become more apparent upon reference to the following specification taken in connection with the accompanying drawings in which:

FIGURE 1 is a perspective view showing an extension arrangement according to the present invention;

FIGURE 2 is a sectional view indicated by line 2-2 on FIGURE 1;

FIGURE 3 is a sectional view indicated by line 33 on FIGURE 1 showing the door of the unit open to give access to the fuses therein;

FEGURE 4 is a view looking in at the said door showing the arrangement of the fuses therein;

FIGURE 5 is a diagrammatic representation of th electrical circuit of the modification of FIGURES 1 through 4;

FIGURE 6 is a perspective view of a modification in which an automatic mercury switch is provided for deener izing the outlets when the box at the outlet end of the extension is open;

FIGURE 7 is a fragmentary view showing how the switches of the FIGURE 6 modification are enclosed to protect against accidental touching of the terminals thereof; and

FIGURE 8 is a fragmentary view showing another manner in which a mercury switch could be incorporated in the unit.

Referring now to the drawings more in detail FIG- 3,lr'33,l28 Patented Dec. 29, 195-4 URE 1 shows an extension cord 10 having a plug 12 at one end for being plugged into a receptacle while at the other end of extension cord lti there is a box 14. Box 14 has a plurality of electrical outlets 16 distributed thereover as, for example, on the sides and ends and, if desired, on the top. There is also preferably mounted in the box an on-off switch 18 which, in its oil position, 'isconnects the extension from the receptacles 16 while in its on position these elements are connected.

FlGURE 2 shows one possible arrangement of the outlet 16 and the on-off switch 18 in box 14. Box 14 comprises the box-like portion in which the aforementioned elements are mounted and a lid or door member 20 hinged to the box portion as by hinges 2.2.

As will be seen in FIGURES 3 and 4 the door portion is availed of for supporting a plurality of fuses 24 which are held in the clips 26 in a somewhat conventional manner. Preferably, the fuses are confined between wall portions 28 extending outwardly from the lid or door thereby effectively isolating the fuses from each other.

The fuses are for the purpose of providing individual protection for the several receptacles carried by the box and in addition thereto provide a main fuse in the extension line leading to the receptacle. This provides the convenience of maintaining electric power to most of the receptacles, even though one fuse blows Whereas the entire unit is protected from excessive overloads by the single main fuse provided in the unit. The receptacle into which plug 12 of the extension is plugged could, of course, be provided with its own fuse, but this would be relatively large fuse so that under all normal cir cumstances, any fuse that would blow out would also be located in the box 14.

FIGURE 5 shows how the fuses 24 are arranged in circuit with the on-otl' switch 18 and the receptacle 16 and the extension line 10.

FEGURE 3 also illustrates how an auxiliary switch 3% could be provided having an actuating plunger 32 so that whenever the lid or door 26 was open actuating element 32. would be released and switch 3-9 would be open. Upon closing of the lid, it is latched closed by means of the spring clip and at this time would hold plunger 32 of switch 3i inwardly and this would close switch and again energize the receptacle to.

The unit as described is adapted for being placed on the floor or on a wor: bench or table or in any other convenient location. [he unit, however, could also be wall mounted as illustrated in FIGURE 6 wherein a unit substantially identical is described illustrated wherein corresponding parts and numbered corresponding with use of a subscript a.

in FZGURE 6 the lid Ella has the projections 36 f 1' receiving screws 3& to secure the unit to a wall The arrangement of FlGURE 6 is characterized by the mercury switch means 42. that are held closed by the linkage 44 when the box portion is closed on the lid portion Eda. Mercury switch 42 is pivotally mounted on the ide wall of box 314a to rotate in the directions shown by the arrows in FIGURE 0. As linkage 44 advances into the box to lid closing position, the upturned extremity of linkage 44 willcause the switch to rotate in a clockwise direction to shift the mercury and complete the circuit. However, upon openin of the box portion to gain access to the fuses carried on the lid portion, the mercury switch means 42 will be rotated in a counterclockwise direction by linkage to open the switch thereby deenergizing the circuits leading to the receptacles and to the fuse clips so that the fuses could be changed without any danger.

A mercury switch could also included on the first iodiiication as diagrammatically illustrated in FIGURE 8. In this figure the mercury switch 46 is secured to the under side of the top surface of the box as indicated in dot-dash outline in FIGURE 1. Upon turning of the box on its side or upon turning the box over so that the lid could be opened the mercury switch means 46 would open and disconnect the extension line it from all of the components in box 14 and on lid 2%. c

It will be understood that mercury switch means 46, as Well as mercury switch means 42, would probably contprise two individual mercury switches for interrupting bothsides of the extension line so that there would be absolutely no possibility of any of the components in the box or on the lid being energized when the mercury switch means are open,

The device of the present invention is relatively inexpensive and is convenient to use and represents a safe manner in which a plurality of tools or appliances can be operated from a single electrical outlet. A It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions; and accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

I claim:

1. An electrical extension; an electric cord, a plug at one end of the cord, a box-like structure into which the other end of the cord leads, a plurality of receptacles in said box-like structure accessible through the walls of the structure, and circuit means interconnecting said plurality of receptacles with said electric cord and comprising fuse means in circuit with each said receptacle and located in said box-like structure, an on-oif switch in said box-like structure operable for disconnecting the circuit means to said receptacles from said electric cord, the said box-like structure including a movable lid portion for gaining access to the interior of said box-like structure for replacement of fuses therein, and means operable in response to opening of said lid for disconnecting the said circuit means to the receptacles from said electric cord.

2. An electrical extension; an electric cord, a plug at one end of the cord, a box-like structure into which the other end of the cord leads, a plurality of receptacles in said box-like structure accessible through the walls of the structure and circuit means inter-connecting said plurality of receptacles with said electric cord and comprising, fuse means in circuit with each said receptacle and located in said box-like structure, an on-off switch in said box-like structure operable for disconnecting said receptacles from said electric cord, and said box-like structure including a moveable lid portion for gaining access to the interior of said box-like structure for replacement of fuses therein, and means operable in response to opening of said lid for disconnecting the said circuit means to the receptacles from said electric cord, said means comprising switch means having an operating member adapted for engagement by said lid when the latter is closed for closing said switch and for opening said last named switch means when said lid is opened.

3. An electrical extension; an electric cord, a plug at one end of the cord, a box-like structure into which the t other end of the cord leads, a plurality of receptacles in said box-like structure accessible through the walls of the structure, and circuit means interconnecting said plurality of receptacles with said electric cord and comprising fuse means in circuit with each said receptacle and located in said box-like structure, an on-otf switch in said box-like structure operable for disconnecting said receptacles from said electric cord, said box-like structure including a moveable lid portion for gaining access to the interior of said box-like structure for replacement 5 fuses therein, and means operable in response to opening of said lid for disconnecting the said circuit means to the receptacles from said electric cord, said means comprising mercury switch means having a circuit closing position and a circuit interrupting position, and means operatively connecting said mercury switch means with said lid for movement of the switches into circuit opening position when the lid is open and into circuit closing position when the lid is closed. r

4. In an electrical extension; an electric cord having a plug at one end, a box-like structure into which the other end of the cord leads, said box-like structure having receptacles mounted in the walls thereof so as to be accessible from outside the box-like structure for receiving plugs while having the electrical connections thereto on the inside of the box-like structure, said box-like structure having a lid hinged thereto, fuse means carried on the inside of the lid connected in circuit between said electric cord and said receptacles, and mercury switch means in said box-like structure between the said electric cord and the said fuse means arranged within the structure so as to be in closed position when the structure is resting on one face thereof and to be in open position when the structure is resting in any other position.

5. In an electrical extension; an electric cord having a plug at one end, a box-like structure into which the other end of the cord leads, said box-like structure having receptacles mounted in the walls thereof so as to be accessible from outside the box-like structure for receiv ing plugs while having the electrical connections thereto on the inside of the box-like structure, said box-like structure having a lid hinged thereto, fuse means carried on the inside of the lid connected in circuit between said electric cord and said receptacles, and mercury switch means in said box-like structure between the said electric cord and the said fuse means arranged within the structure so as to be in closed position when the structure is resting on one face thereof and to be in open position when the structure is resting in any other position, there also being an on-oif switch carried by the structure in the circuit between said cord and said receptacles operable for selectively electrically disconnecting said receptacles from said electric cord.

References Cited in the file of this patent UNITED STATES PATENTS Clayton Mar. 14, 1944 Jensen Jan. 23, 1962 OTHER REFERENCES 

1. AN ELECTRICAL EXTENSION; AN ELECTRIC CORD, A PLUG AT ONE END OF THE CORD, A BOX-LIKE STRUCTURE INTO WHICH THE OTHER END OF THE CORD LEADS, A PLURALITY OF RECEPTACLES IN SAID BOX-LIKE STRUCTURE ACCESSIBLE THROUGH THE WALLS OF THE STRUCTURE, AND CIRCUIT MEANS INTERCONNECTING SAID PLURALITY OF RECEPTACLES WITH SAID ELECTRIC CORD AND COMPRISING FUSE MEANS IN CIRCUIT WITH EACH SAID RECEPTACLE AND LOCATED IN SAID BOX-LIKE STRUCTURE, AN ON-OFF SWITCH IN SAID BOX-LIKE STRUCTURE OPERABLE FOR DISCONNECTING THE CIRCUIT MEANS TO SAID RECEPTACLES FROM SAID ELECTRIC CORD, THE SAID BOX-LIKE STRUCTURE INCLUDING A MOVABLE LID PORTION FOR GAINING ACCESS TO THE INTERIOR OF SAID BOX-LIKE STRUCTURE FOR REPLACEMENT OF FUSES THEREIN, AND MEANS OPERABLE IN RESPONSE TO OPENING OF SAID LID FOR DISCONNECTING THE SAID CIRCUIT MEANS TO THE RECEPTACLES FROM SAID ELECTRIC CORD. 